Sheet-metal joint.



PATENTED MAY 8, 1906.

J. E. DOBSON. SHEET METAL JOINT.

APPLICATION FILED JAN. 24. 1905.

f/LL mu Lapin/as: ea ca-c/ 5 of Michigan, have invented UNITED STATES PATENT oFFIon.

JOHN E. DOBSON, OF YPSILANTI, MICHIGAN, ASSIGNOR TO MICHIGAN MACHINERY MANUFACTURING COMPANY, OF YPSILANTI, MICHI- GAN, A CORPORATION OF MICHIGAN.

SHEET-METAL JOINT- Specification of Letters Patent.

Patented May 8, 1906.

To all whom it may concern..-

Be it known that I, JOHN E. DOBSON, a citizen of the United States, residing at Ypsilanti, in the county of Washtenaw and State certain new and useful Improvements in Sheet-Metal Joints, of which the following is a specification, reference being had therein to the accompany- 'ing drawings.

: The invention relates to a construction of joint between sections of sheet metal, being more particularly designed for the formation of metallic rings, such as are employed in stove construction.

It is the object of the invention to obtain a flush joint formed without brazing or welding and one in which the adjoining sections cannot become detached from each other.

To this end the invention consists in the 0 construction hereinafter set forth.

In the drawings, Figures 1 and 2 illustrate, respectively, the first and second steps in the process of forming the joint. Fig. 8 is a cross-section illustrating the second step in 5 the process. Fig. 4 is a perspective view of the completed joint. Fig. 5 is a perspective view of the ring embod g the joint, and Fig. 6 illustrates a modifi tion.

In the present state of the art fiat sheetmetal sections have been joined to each other by forming in the adjacent edges of the blank complementary teeth or indentations, which are ada ted to intermesh and interlock with each ot er. The sections thus joined are held from dis lacement in relation to each other in the plgne of the blank, but may be disengaged by a relative lateral movement. In the present construction a joint of the character above described is first formed between sections of the flat metal blank, and after these sections have been engaged with each other they are permanentl locked by the subsequent bending of t e blank. This bending is transverse to the line of the joint, and the effect is to cause the engaged teeth in one portion to lock the engaged teeth of another portion from lateral relative movement. Thus the sections cannot be disengaged one from the other.

1 As shown in Fig. 1, A is one section of the flat sheet-metal blank, and B is the other section thereof. The adjacent edges of these sections are provided with com lementary teeth a and notches b, so that the two sections may be engaged with each other by the slipping of the teeth of one into the notches of the other, as shown in Fig. 2. The blank is then bent into a curved cross-section, preferably by placing it between dies, such as C and D. Where the article to be formed is a ring, such as is illustrated in Fig. 5, the blank is first formed into a plain hoop and the edges joined, as in Figs. Land 2, after which the hoop is placed between the dies and drawn into the curved cross-section shown in Fig. 4.

It is apparent that in the curved cross-section the adjoining faces of the teeth are not parallel, but are at an angle to each other, and as a consequence each tooth operates to lock the other teeth from disengagement from each other. In other words, the opposite edges of a tooth are not in the same plane. The same result is obtained where the final form is one in which there are fiat portions of the blank which stand at an angle to each other, as illustrated in Fig. 6.

What I claim as myinvention is 1. In a joint for sheet-metal sections, complementar teeth on the ends of the sections intermes 'n in different planes, the coaction of said teet locking the sections from movement in any direction and forming a joint of a thickness equal to the thickness of the teeth.

2. In a joint for sheet-metal sections intermeshin complementary teeth the opposite edges 0% each tooth being in different planes, for the purpose described.

3. A joint between sheet-metal sections, consisting in intermeshing and interlocking teeth formed on the adjoining edges of the two sections, the plane of the interlocked pair of teeth in one portion of the line of joint being out of angle to the plane of the interlocked pair of teeth in another portion of the line of oint.

4. A joint for sheet-metal sections comprisin intermeshing and interlocking teeth on the a joining edges of the two sections, the longitudinal section of the line of joint being curved.

In testimony whereof I affix my signature in presence of two witnesses.

JOHN E. DOBSON.

Witnesses:

H. C. SMITH, EDWARD D. AUL'r. 

